On Christmas, during a feist, a man in green came in with a green horse. He held an ax and asked if anyone wanted to cut his head off. Sir Gawain said he would, and so he did. He cut the Green Knight's head off. But then the body picked up the head and the head said where to meet him.
When Gawain traveled to meet the Green Knight, he stopped at a castle to rest. The lord there was very kind. They both made a deal, the lord would give Gawain whatever he finds in the woods he would give him in exchange for whatever he finds in the castle. The first night, the lady of the castle came to kiss him. The next day, Sir Gawain went and kissed the lord of the castle. Gawain spent three nights there, including the first.
When Gawain finds the Green Knight and the Green Knight tells him to neal down so that he can cut his head off just like how he did to him. The Green Knight tries to cut his head off, but he didn't. He says that he has been doing wright. He has shown his knight hood.
When King Arthur is hunting with other knights, he finds a knight with a sword in his body carried by four squires. He says he can only be healed by a knight there.
Lady Nimue brings Arthur Sir Launcelot of the lake. He has his half brother and his cousin with him. Launcelot removed the sword from the kinght and heals him.
Sir Launcelot disuses himself as Sir Kay in a jousting tournament. because he is not very good fighter and he is not very popular. The knights do not know that it is Launcelot. He beats them all in the tournament. One knight later realizes it is Launcelot in a feast.